The present invention relates to a cassette with consumable tape, in particular for transport ticket processing device.
It has a general application for consumable tape, and more particularly for inking tape used in particular for thermal printing, for example, for processing transport tickets.
Cassettes with consumable tape are already known. In the International Application published with no. WO 96/11872, a replaceable cassette comprises a carcass supporting rotatably two reels on each of which is wound a tape from one of its ends, each reel comprising an axial bore in order to be fitted on to a spindle of a ticket processing device intended to receive the cassette.
The cassette comprises disengageable locking means to prevent each reel from turning in the direction of slackening of the tape. Before mounting of the cassette, these disengageable means keep the two reels in a position where the tape is taut in the region where it must be positioned relative to the thermal printing device.
In practice, the disengageable locking means comprise two toothed discs (one per reel) and two ratchets each cooperating with the toothing of one of the discs in order to prevent rotation of the corresponding reel in the direction of slackening of the exposed region of tape. The two ratchets are opposite one another and are formed as a single spring blade with an actuating region joining them. When the two ratchets are in an active position, each reel can only turn in one direction, contrary to that allowed for the other reel, and corresponding to an increase in tension of the exposed region of the tape.
During manufacture of the cassette, a reasonable tension is imparted to the tape and in particular to its exposed region, and this tension is maintained during transport, storage and fitting of the cassette by virtue of the disengageable locking means, which remain active throughout this period.
Such locking means are not totally satisfactory. In fact, the tape may slacken, for example, due to changes in temperature and impacts which may arise during transport or storage of the cassette. This slackening of the tape cannot be compensated, since the reels are locked in a fixed position. Consequently, insertion of the cassette into the receiving device may be interfered with, sometimes to the point of damage to the tape.
Moreover, the locking position of the reels depends on the play of the toothing of the wheels cooperating with the ratchets, which makes such locking imperfect.
Finally, the disengagement of the locking means is generally effected by an operator, and this manual operation is generally difficult to carry out.
The present invention brings a solution to these problems.
It relates to a replaceable tape comprising first and second rotating reels on each of which is wound a tape starting from one of its ends, each reel being capable of fitting over a spindle of a receiving apparatus.
According to a general definition of the invention, the cassette comprises a mechanism for tensioning the tape, capable, when the cassette is outside the receiving apparatus, of keeping the tape taut in a substantially constant manner even in the case of impact, change of temperature, mechanical stress or the like.
Thus, by virtue of the tensioning mechanism of the tape according to the invention, the tape is kept constantly taut even in the case of impacts or changes of temperature during transport, storage or fitting of the cassette in the receiving apparatus.
According to a first embodiment of the invention, the mechanism of the invention comprises:
first means of driving rotatably the first reel in a first direction,
locking means capable of rendering non-rotatable the second reel, and
means forming a resilient recall, capable when the cassette is outside the receiving apparatus of applying a stress to the first drive means and to the locking means, such that with the second reel locked, the first drive means drive rotatably the first reel until the tape reaches a selected position of tension, the stress of the means forming a resilient recall, making it possible to keep the tape taut according to the selected tension position, whatever the conditions of transport, storage, impact, temperature, mechanical stress or the like.
According to a second embodiment of the invention, the mechanism of the invention comprises:
first means for driving rotatably the first reel in a first direction,
second means for driving rotatably the second reel in a second direction, contrary to the first direction,
means forming a resilient recall, capable, when the cassette is outside the receiving apparatus, of applying a stress to the first and second drive means, such that the first and second drive means drive rotatably respectively the first and second reel in their respective directions until any slack in the tape is compensated and the tape is brought into a selected tension position, the stress of the means forming a resilient recall making it possible to keep the tape taut according to the selected tension position, whatever the conditions of transport, storage, impact, temperature, mechanical stress or the like.